Covalent Inhibition of the Human Papillomavirus Type 16 E6 Protein Restores p53 and Suppresses HPV-Driven Tumorigenesis

Abstract

High-risk human papillomavirus (HPV) infections are the etiology of approximately 5% of all cancers worldwide, including cervical, anal, and oropharyngeal malignancies. HPV E6 is a multifunctional oncoprotein that drives tumorigenesis and is best known for bridging the ubiquitin ligase E6AP (UBE3A) and p53 into a complex that leads to proteasome mediated destruction of p53. We developed small molecule inhibitors that covalently bind to cysteine-51 (Cys-51) in HPV16 E6. In HPV16-positive cancer cells, these compounds increase p53 protein levels and activate p53-dependent transcriptional programs associated with apoptosis and senescence, resulting in reduced tumor cell viability. In vivo, E6 inhibition suppresses the growth of human HPV16 expressing cervical and oropharyngeal tumor cell lines in mice. The strategy of targeting a viral oncoprotein with a covalent inhibitor demonstrates a genotype-specific therapeutic strategy for HPV-associated cancers and premalignant infections, addressing a significant unmet need in current treatment options.